displacement during constant acceleration

Question

A car is brought to rest in a distance of 484 m using a constant acceleration of -8.0 m/s². What was the velocity of the car when the acceleration first began

Answer 1

Use the kinematic relation

v² - v₀² = 2ad ⇒

v₀ = √(v² - 2ad)

Plug in

v = 0 (full stop)

d = 484 m

a = -8.0 m/s²

and get v₀ in m/s. It will come out positive.